Air control device



iiill utenteci Sept. 24, 1940 UNITED STATES PATENT OFFICE 2 Claims.

My invention relates to an air control device and in particular to a device for the automatic regulation of the volume of air and the volume of liquid in the pressure tank of an automatic liquid supply system.

Small water supply units commonly consist of a motor means driving a pump which lifts the Water by suction from. a well or other source, forces the water under pressure into a tank partly filled with air which is thereby compressed and when the pressure in the tank has reached an upper limit, a pressure actuated valve or switch stops the motor means and the pump. When the pump is at rest in such a system, the pressure is till maintained on the suction side by check valves in the pump or in the suction pipe. Upon drawing water from the system, as by opening a. faucet in the delivery line, the compressed air in the'tank forces out some oi the water until the pressure has reached a lower limit at which time the switch or valve for the motor means is automatically actuated and the pumping oi the water again starts and continues until the upper limit ing pressure again stops the pump. In order to provide a smoothly operating system, a suitable relative volume of air and water in the tank is required, both at the highest pressure and at the lowest pressure, (operative pressure limits determined by the settings of the pressure actuated valve or switch controlling the motor and the pump), and since air is absorbed by the fresh water, particularly under pressure, it is necessary to provide some means of introducing additional amounts of air to replenish the supply in the pressure storage tank. If this is not done the system becomes water-logged" and ceases to iunetion properly. Various devices for introducing air into the tank. have been used; particularly with cylinder pumps, but none has been wholly satisfactory, because of the necessary delicacy oi ediustuient, because of the wear of ports operat'. with each stroke of the pump, because of the uncertainty of operation of float valves which are essential parts of most of these devices, and because in operation these devices decrease the water delivery capacity oi the pump. None of these devices, so far as i am aware, are adapted for use with. centrifugal pumps.

The object therefore of my invention is to provide an auxiliary air pump which automatically maintains the desired proportion oi air and liquid volumes in the pressure tank for a liquid supply system. Another object is to provide a device which maintains the level of water in a pressure Water supply tank; at the desired level. Another object is to provide a device for maintaining the water level in a water pressure tank system which is actuated by the changes in pressure on the suction side between the running and stopped condition of the pump. Still another object is the provision oi. a device for automatically maintaining the water level in a pressure water supply tank and system including a centrifugal pump.

The invention will best be understood by refer ence to the accompanying drawing in which:

Fig. l is a cross sectional view of a preferred form of my device taken on the line l-.l of Fig, 2;

Fig. 2 is a front elevation of my device;

Fig. 3 is an enlarged cross-sectional view of the nozzle 2! taken on the line 3-3 of Fig; 1;

Fig. 4 is a diagrammatic view showing the use of my control device in a unit water system having e. pressure supply tank and a centrifugal pu p;

Fig. 5 is a diagrammatic view showing the use of my controldevice in a water system having a pressure supply tank and a reciprocating pump;

Fig. 6 is a cross-sectional view of another form of my device using a metal bellows of the Sylphon" type:

Fig. 'l' is an elevation, partly in section showing another form of my device involving a float valve.

Referring to the drawing: ll represents generally a housing for the device, preferably made in two pieces i2 and i3, bolted together by bolts 25. Between the two parts l2 and I3 is held a circular diaphragm it which may be of flexible metal. sheet rubber, gasket composition or other flexible material. The diaphragm preferably fits smoothly against the inner surface I5 0! the part ll of the housing, in order to completely expel the intaleen air and water, but this diephragm may also be arranged as a partition divlding the casing. In any arrangement, the essential idea is to form with the casing a simple diaphragm or bellows pump which may be contracted and expanded to draw in and expel air or water through the inlet and outlet ducts. A. thrust plate it attached to a compressed spring ll holds the diaphragm M against the surface it. A vent plug in the casing is indicated at A pipe coupling means IS on the part 13 of the housing is attached for connection to the suction side of a pressure pump for liquids by a pipe 39. ihe part it of the housing is provided with a neck it which has outside threads for screwing into a tapped hole in the water tank at the low water level L in the tank, it being intended that the device be supported on the tank by this neck.

Through the neck I9 is a discharge aperture 2t leading from the diaphragm contact surface to the outer end of the neck, communicating when installed on a pressure. tank, with the inside contents of said tank. In this discharge aperture 26, near the outer end, is inserted an elongated apertured plug or nozzle 2| which as shown has a small groove 22 cut in the upper edge and is threaded into the hole 20. Attached to the neck l9 by means of a threaded hole connecting with the discharge aperture 20 by the threaded hole 24 is a spring controlled air valve or snlfier" valve 23. A vent plug 60 permits removal of air and filling with water of the cavity back of the diaphragm |4. When suction is applied through a pipe connection 39 attached at I8, the diaphragm i4 and the thrust plate l6 take the position roughly indicated by the dotted lines and the spring I! is compressed.

The nozzle 2| is preferably made so that the opening 22 is locatedat a position which minimizes the danger of entrapping air which interfers with the smooth operation. For the same reason the neck l9 and the hole 20 therein is preferably located near the top of the device and inclined to prevent trapping of air.

Referring particularly to Fig. 4, a pressure storage tank 30 is equipped with a pressure indicating gauge 3|. An electrical motor 22 whose operation is controlled by the automatic pressure actuated electrical switch 33, which is operatively connected to the water delivery line 34 and also electrically connected to the power line leads 42, operates the centrifugal pump 35, whose suction line 3% draws water from a well 31 and has a foot valve or water check valve 38 below the water level in the well. The control device of my invention is installed at the low water line as indicated at L, by means of the threaded neck t9, the casing being indicated at H and having the .part It connected by means of a small copper operated reciprocating plunger type. In this Fig.

the storage tank 30 has an indicating pressure gage 3|, an inlet and discharge pipe 34 connected at one end near the bottom of the tank and at the other to the discharge side of the reciprocating pump and also to the delivery pipe 43 for the system. A conventional steam engine is diagrammatically represented at 44 having a steam supply line 45 controlled by a valve 46 which is automatically regulated by a pressure sensitive device 41 which in turn is actuated by the varied pressure on the water delivery line 34 with which it is connected by the pipe 48. The water control device of my invention is attached to the tank at the low water level indicated at L by means of the neck l9, and is connected by the pipe 39 attached to the casing of the control device at the pipe coupling means l8, and also to the valve chamber of the reciprocating water pump at a point between the inlet and outlet valves of said pump indicated at 49. In the arrangement shown the connection from the coupling IS on the device is made to the valve chamber rather than to the suction line 36a outside the pump, since it is not usual practice to employ a foot valve to retain the pressure in the system but to depend upon the regular valve in the pump to prevent the loss of leveling device may be used in the same manner as with a centrifugal pump, with the pipe 39 then being connected to the suction line between the valve and the pump. To insure that the pressure in the system down to the check valve in. the suction line will be equalized when the pump L at rest, small openings or notches may be made in the intake valves and in the discharge valves of the reciprocating pump. These small openings (not indicated in the drawing) will not interfere with normal pumping operations, but, when the pump is stopped will allow equalization of pressures after a short time, and consequent closing of the diaphragm l4 and the discharge of air into the tank.

Fig. 6 shows another form of my device which employes a metallic bellows of the Sylphon type. In place of the flexible partition diaphragm l4 as indicated in Fig. 1, in this Fig. 6 the metallic bellows is indicated as Ma. A vent plug is indicated at 50, which permits filling with water of the space outside the bellows.

The high water level in the tank is indicated on Figs. 4 and 5 by the line H and the low water line by the line L.

The operation of my device, as illustrated for example by reference specifically to Fig. 4, is as follows: when the water level is below the low level L and the pressure in the tank has reached such a low point that the pressure actuated switch 33 starts the motor and the centrifugal pump 35, the suction created by the pump in the suction line 36 also produces a negative pressure back of the diaphragm R4 in my control device, this causing the diaphragm to pull back to the position shown by the dotted lines in Fig. l and also compresses the spring ll. The diaphragm is held in this position so long as the pump is in operation and there is sufficient suction on the line 36. The diaphragm in moving to this "open position creates a suction in the inlet tube 2| and air is drawn in from the tank. The sniffer valve 23 does not open under these conditions because thereis'only a little friction in the passage of air under pressure from the tank through the restricted or capillary opening 22 of the nozzle 2|. After the pressure in the tank 30 has been raised by the additional water pumped into the tank by the pump operation, a pressure sufficiently high to actuate the pressure switch 33 is developed in the tank and the motor and pump are automatically stopped. The tank pressure then prevails throughout the system including the pump and suction line 36 down to the foot valve 38, and the pressure on the two sides of the diaphragm I4 is equalized and the spring l'l forces the air between the diaphragm and the casing wall i4 through the duct 29 and the nozzle 22 back into the tank. The tank then supplies water under the pressure of the compressed air in the tank until the pressure has again become solow that the motor and pump are started by the closing of the pressure actuated control switch 33. The water level is, however, no longer at L, the lower limit, but is somewhat above this so that the nozzle 22 is submerged by water. Under these conditions when the pump starts as before, the suction applied to the lines 36 and 39 pull the diaphragm back against the compressed coiled spring ll. This creates a suction in the outlet tube 28 and its nomle 22, but since the nozzle is under water, the intake of air from the tank is prevented. Because of the higher friction of the water through the small opening 22, enough auction or negative pressure is created by the drawing back of the diaphragm to cause the opening of the snifler valve 23 so that a mixture of air train the atmosphere together with the small amount of water "which comes in through the opening m2 is drawn into the space between the inside surface ii of the case part I! and the diaphragm ll in its open position. While the pump is running this air and water is held in the open" diaphragm or bellows pump arrangement but when the pump 35 has again brought the pressure in the tank 30 to a suiflciently high point to actuate the motor control switch 33, the pump tilt stops and the pressure on the system, including not only the tank but also the suction line down to the 2% foot valve 38, attains the same pressure as that in the tank. Consequently since the hydraulic pressure in either side of the diaphragm is now equalized, the diaphragm is forced back to the surface it by the pressure of the spring l'l acting against the thrust plate II, and the contents of air and water is forced out into the tank 30 through the nozzle 22. It is thus seen that additional amounts of .air from the atmosphere are introduced into the tank upon each stopping of the pump provided the level of the water at low pressure is above the orifice 22, but if the low water level is below the orifice 22 then no air is drawn in through the miller valve II. Depending upon the prevailing conditions in any particular installation, the capacity of my control device may be adapted to introduce the correct amount of air. The capacity for delivery of air of my device might be made too small for a given tank and pump unit and would not introduce enough air to prevent "water log ing. but

it would function properly even if larger than really necessary.

In a similar manner the water leveling device operates with the reciprocating water pump eyea tem diagrammatically shown in Fig. 5. When the low water level covers the orifice 12 and the pump "a is set in operation through the steam control valve 41 actuated by the pressure within the tank, then a suction is created in the pipe 3! -50 by the movement of the pump piston in sucking water into the pump valve chambers. when the pump is stopped and this suction is relieved and the water pressure in the system equalized, then the diaphragm I I is forced back by the spring I! w to its original position, expelling the charge of atmospheric air and a little water into the tank as previously described for the diagrammatic setup of Fig. 4. The change in pressure in the valve chamber upon reversal of the piston may cause a slight pulsation of the diaphragm but this will not be great enough to cause the diaphragm to function with each piston stroke, but only upon starting and stopp The operation of the metallic bellows as iliustrated in Fig. 6 is analogous to that described for the diaphragmatic type shown in lids". l. The inherent contraction of the metallic or Sylphon" type bellows is augmented, where necessary, by a compression coil spring it in a manner analogously described for the preferred form of the device shown in Fig. 1.

Instead of the elongated restricted nozzle 2|, I may use, as shown in Fig. l, a. one way float valve Bl having a check valve inside the tank which closes the port 20 to the tank when the level of water in the tank is too high, permitting atmospheric air to be drawn in through the "sniffer valve into the bellows or diaphragm pump of my control device, to be expelled into the tank when the pump is at rest through the check valve M which consists, for example, of a ball I I, a ball seat 82 and a light spring 83 to hold the ball with very light pressure against the seat. When the water level in the tank is below the opening of the port 20 inside the tank, the float valve remains open and the diaphragm. merely draws in air from the tank and puts it back again when the pump is in operation and at rest.

Although I have shown and described specific embodiments of my invention, many modifications are possible and my invention is, therefore, to be restricted only insofar as is necessitated by the prior art and the appended claims.

I claim:

1. In a water supply pressure system, in combination, a water pressure pump, actuating means for said pump, means for starting and stopping said pump, a tank for receiving and storing water under pressure from said pump and air under pressure, an auxiliary air pump for supp air under pressure to said tank, an atmospheric inlet to said air pump, and a regulating device for maintaining a desiredproportion of air and water in said tank, said regulating device comprising a duct between said air pumpand said tank, the opening within the tank being dis-. posed at the desired water level in said tank, a one-way valve at the end of said duct within said tank, a float means for opening and closing said one-way valve when the water is below and above, respectively, the desired water level in the tank, means whereby said auxiliary air pump is actuated by the changes in hydraulic pressure on the suction side of the water pump, said atmospheric inlet being adapted to admit air through it to said air pump only when said one-way valve has been closed by said float.

2. A device for regulating the level of liquid in a pressure tank system comprising an intermittently operating liquidpressure pump, a tank to receive liquid from said pump, an auxiliary air pump having a combined inlet and dischargeduct between it and the inside of said tank at the desired liquid level in said tank, a stopper-valve seated in said duct near its tank end, a one-way discharge control valve in said stopper-valve opening toward the tank, means actuated by a host on the liquid within said tank for removably holding said stopper-valve in closed position in said duct, a check-valved air inlet communicating with said duct and adapted to admit atmospheric air when the stopper-valve is closed, and means whereby said auxiliary air pump is actuated by the changes in hydraulic pressure on the suction side of the liquid pump.

MILFORD W. HARIMANN. 

